The proteins which are secreted by Sertoli cells in culture will be isolated and characterized. Monoclonal antibodies to each of the secreted proteins will be generated and the antibodies and the proteins themselves will be used to probe for the function of all of the secreted proteins. Germinal cells will be isolated and the interaction of the germinal cells with the isolated proteins will be studied. The regulation of Sertoli cells by a number of hormones will be examined and optimal serum-free culture conditions will be determined. We will examine the effect of these hormones on Sertoli cell mRNA synthesis and the translation products of isolated mRNA. Sertoli cell lines which are already established will be used to form new cell lines by hybridization with primary Sertoli cells.